You guys need to make a playlist just for a specific game and not group all 4 halo's into one playlist like big team battle. Make a big team battle for halo 1, halo 2, halo, 3 and halo4. Have them separate. For example I wanted to just play Halo 1 team slayer and couldn't do that cause there are no halo 1 playlists for me to join! If need be you should organize the matchmaking playlists like the example below.
Matchmaking
. Halo MCC
o Slayer
o Big Team Battle
. Halo 1
o Slayer
o CTF
o Big Team Battle
. Halo 2
o “”
. Halo 3
o “”
. Halo 4
o “”